In a 1963 letter to publisher Timothy O’Keeffe, the author professed “a horrible fear that some stupid critic will praise me as a master of science fiction”. I’ll avoid using the M-word, but the fact remains that a number of his works fit the definition comfortably. His early fiction and his later Cruiskeen Lawn column make fun of sci-fi tropes as often as anything else, and his undisputed masterpiece, The Third Policeman, is full of bizarre concepts derived from scientific principles taken to absurd extremes – see “the atomic theory” and the hypothesis that excessive use of a bicycle will turn a cyclist into their vehicle. When The Third Policeman was rejected by publishers, O’Brien reworked material from it into The Dalkey Archive, which features time-travel (of a sort) and a mad scientist who wants to end the world.